The cost to bury power lines underground per mile has fallen from 4 million to 3.1 million dollars for Pacific Gas and Electric

The cost to bury power lines underground per mile

Pacific Gas and Electric says the cost to bury power lines underground per mile, the main defense it has against a line sparking a wildfire, has fallen from 4 million dollars at the start of its undergrounding program in 2021 to 3.1 million dollars in 2025. The company reported the decline directly to an industry news outlet in October 2025. The decline continued, the company told a Sacramento television station in August 2026, to approximately 3 million dollars a mile. Undergrounding means moving a power line from poles overhead into buried cable, so wind cannot knock the line into dry vegetation and start a fire.

How Pacific Gas and Electric cut the cost

The company attributes the decline to hiring local contractors, using specialized construction equipment, reducing trench depth and width, repurposing soil dug from each project site, and no longer needing the ongoing vegetation management that overhead lines require. Matt Pender, Pacific Gas and Electric vice president of Undergrounding and System Hardening, described testing a new trenching machine called the Bulldog Trencher in August 2026.

This piece of equipment has done more than 1,000 feet today by cutting a pretty narrow trench road where we can put our power lines.

Matt Pender, Pacific Gas and Electric vice president of Undergrounding and System Hardening. Source 2.

The company estimates the machine can save up to 40,000 dollars a day on a project. It also says it expects to reach about 1,600 miles of underground line statewide by the end of 2026, a projection stated in both of the sources this cost figure comes from. Underground lines are expected to last at least 60 years once buried, longer than the poles they replace.

Executives tie the savings to scale

Peter Kenny, Pacific Gas and Electric senior vice president of Electric Operations, tied the 2 trends together directly in 2025, connecting the pace of construction to the falling cost.

Well, not only are we at 1,000 miles and counting, but we also have substantially reduced the cost for our customers as we've scaled up our work.

Peter Kenny, Pacific Gas and Electric senior vice president of Electric Operations. Source 1.

A 95 page plan with no price on it

Pacific Gas and Electric own filed 2026 to 2028 Wildfire Mitigation Plan Overview, a 95 page document the company files with state regulators, tracks the same program in miles completed but never once states a dollar cost. A full text search of that filed plan for the words million, billion, cost and unit cost returns 0 matches. The filing instead states the company had constructed more than 725 miles of underground line as of June 30, 2025, reaching more than 1,000 miles by October 2025 and more than 1,370 miles by September 2026. Every dollar figure in this cost decline comes only from what company executives told reporters directly, not from the paperwork Pacific Gas and Electric files with regulators.

Why the company is willing to spend this much

The spending targets a specific kind of disaster. Undergrounding eliminates nearly all wildfire risk from a line once complete, the company states in its own filed wildfire plan. The state own fire agency attributes the 2018 Camp Fire to power lines, and the blaze burned 153,336 acres, destroyed 18,804 structures and killed 85 people. A mile of line buried today is a mile the company expects never to spark a wildfire again.